Open-ended wrenches have numerous applications wherever any rotatable element, such as an hexagonal nut or bolt, needs to be tightened or loosened. The open-ended variety is especially useful where tight spaces restrict the use of socket wrenches or other closed-end tools. The difficulty with these wrenches, however, is that when the user is using it to turn an element in anything but the most unrestricted of spaces, the wrench must be removed from the element and repositioned every fraction of a turn due to interference with other obstructions. Thus, without adequate space for a full 360.degree. C. turn of the handle, multiple turning strokes must be applied, with repositioning necessary after each stroke. This shortcoming slows the rate at which the element is driven or loosened, making it difficult, and sometimes nearly impossible, to turn elements quickly in tight or awkward spaces.
To solve this problem, various inventors have developed open-ended wrenches with a ratcheting feature so that the removal and repositioning of the wrench is not necessary when applying multiple turning strokes. Some examples of such wrenches are disclosed in U.S. Pat. Nos. 2,730,000; 3,023,654; 3,165,015; 3,306,142; 3,717,054; 4,440,047; 4,637,284; and 4,787,277. In these wrenches, the ratcheting feature is usually implemented in a complicated mechanism on or within the jaws of the wrench.
These prior art devices also have other shortcomings. Most of them have a large number of moving parts which must be precisely machined and fitted within close tolerances. Due to these assembly and manufacturing complications, the cost of purchasing a ratchetable open wrench is substantially greater than the cost of a standard, non-ratchetable model. This cost is significantly multiplied when one recognizes that, since the sizes for such wrenches are fixed and non-adjustable, a user must purchase a large number of wrenches to make a useful and complete set. The large investment involved with more complicated models discourages popular use of these wrenches.
Moreover, the close tolerances and multiple moving parts required in the prior art wrenches causes the wrenches to be more delicate and susceptible to damage with routine use. The small parts can become misaligned or dented, rendering the wrench or its ratcheting mechanism useless. In light of the significant expense involved in making or purchasing such wrenches, their susceptibility to damage makes the wrenches very impractical.